When you say the word “hydrangea,” most people immediately picture the Hydrangea macrophylla mophead and lacecap varieties. These magnificent bushes are highly well-liked and frequently blossom in summer landscapes across the nation. The oakleaf species of hydrangea (H. quercifolia), a less popular variety with a distinctive appearance and texture, is a hydrangea. Oakleaf hydrangeas also produce enormous, spectacular flower clusters, much like the mopheads and lacecaps. However, that is about where the similarities between the oakleaf hydrangea and its relatives end.
The oakleaf hydrangea differs from the other members of the genus in a number of important ways.
- Flowering behaviorOakleaf hydrangeas produce inflorescences, or long, cone-shaped clusters of flowers (flower heads consisting of a group or cluster of flowers arranged on a stem). The inflorescences are made up of both conspicuously fertile and ostentatious infertile blooms. The mophead hydrangeas, on the other hand, feature globe-shaped clusters of sizable florets. The flattened bloom heads of lacecap hydrangeas are flanked by larger male flowers and smaller female flowers.
- Foliage
Oakleaf hydrangea foliage is big (4 to 12 long and wide, depending on the selection), lobed, and coarsely textured, in contrast to the leaves of H. macrophylla species, which tends to be moderately sized, oval or heart shaped, and smooth textured. The botanical name of this shrub, quercus folium, is derived from the Latin words quercus (oak) and folium, which describe the foliage as having a form resembling that of an oak leaf (leaf).
- Origin The 23 identified species of hydrangea that make up the genus are primarily Asian in origin. The smooth hydrangea (H. arborescens) and oakleaf hydrangea are the only two exceptions that are indigenous to this nation. All of the states in the southeastern region of the United States, from North Carolina south to Florida and west to Louisiana, are home to the native oakleaf hydrangea.
- Fall hues
The only plant in the genus that has any discernible fall leaves colors is the oakleaf hydrangea. The oakleaf hydrangea is still fully covered with gorgeous deep crimson to purple leaves in November and December, when the majority of other deciduous plants have lost their foliage. These leaves last well into the winter.
- cultural prerequisites In general, all hydrangeas prefer moist, well-drained soil. The oakleaf species can endure drier soil and more sun than other species in the genus, albeit, once established.
A rounded, deciduous shrub with a mounding form from the ground up is an oakleaf hydrangea. Large clusters of blooms are supported by strong, sturdy stems above typically dark green on top and yellowish green underneath foliage. The stems have appealing tan or cinnamon colored bark that falls off in small pieces. This understory shrub is typically found growing in the wild beside streams, on forested hillsides, and in the shade of mixed hardwood trees. It is an ornamental plant that thrives in a natural or groomed woodland setting that is somewhat shaded, particularly with morning sun and afternoon shade. Some varieties are hardy to zone 5, and it is hardy from zones 6 through 9.
On the wood from the previous year, magnificent clusters of creamy white or pink flowers bloom, depending on the cultivar. While just a few varieties produce double flowers, the majority of them do. The flowers are produced in inflorescences that are 6 to 12 inches long and 3 to 5 inches broad, and they last for at least four to six weeks before turning tan or deep pink. Through the autumn, the blossoms provide interest to the plant by drying in situ.
The list that follows, while not exhaustive, describes a variety of oakleaf hydrangea choices, as well as their typical sizes and floral arrangements. While a few varieties can reach heights of 12 feet or more, the majority of cultivars are medium-sized, with an average height of 5 to 8 feet. There are several compact cultivars that grow to a height of 4 feet or less and with proportionately smaller leaf and flower clusters available for gardeners with tiny gardens.
- 12′ tall by 12′ wide is “Alice.” This is a wise choice for bigger gardens that have the space for a shrub of this size. The enormous white blossoms eventually turn tan in the late summer after maturing to rosy pink. The State Botanical Garden of Georgia’s gold medal award for 2000 went to “Alice.”
- Alison is 8 to 10 feet tall. Despite being comparable to “Alice,” this cultivar is a touch wider and has inflorescences that are held more upright. By the end of the summer, the huge white bloom clusters have turned pink and are now tan.
- Harmony is 10′ broad and tall. This variety has clusters of enormous, many, double, sterile blooms. Branches can bow under their weight. This cultivar, which is extraordinarily lovely but not frequently seen in nurseries, may be a challenge due to the flowers’ weight.
- 6′ tall by 6′ wide is “Amethyst.” Dr. Dirr created a small cultivar whose blossoms change from white to rose. As they become older, “Alice” and “Amethyst” both develop extremely deep pink inflorescences.
- 5 to 6′ tall by 5 to 6′ wide is the “Gatsby Gal.” This, along with the next two choices, are from Proven Winners’ 2016 release of the Gatsby series. Flowers on the shrub ‘Gatsby Gal’ are upright, giving the impression that they are larger than the shrub’s relatively small size.
- Gatsby Moon is 6 to 8 feet tall and 6 to 8 feet wide. The inflorescences are composed of closely spaced, extremely full double flowers similar to those on “Harmony,” as previously mentioned. Instead of turning pink with age, the petals become white to green.
- Gatsby Pink is 6 to 8 feet tall and 6 to 8 feet wide. The enormous, protracted flower heads quickly transition from white to a deep shade of pastel pink.
- Queen of Hearts measures 6.5″ high by 9″ broad. This cultivar was created by the shrub breeding program of the U.S. National Arboretum through the hybridization of the cultivars “Snow Queen” and “Pee Wee,” the same cross that also gave rise to the cultivar “Ruby Slippers” that is detailed below. The blossoms start out white and gradually turn a rich pink hue.
- 6′ tall by 6′ wide is the “Snow Queen.” ‘Snow Queen’ can withstand brighter conditions and retains its single-flowered inflorescences more upright than other varieties. The 2012 Royal Horticultural Society Award of Garden Merit was given to it.
- 7′ tall by 7′ broad is “Snowflake.” This cultivar, like the others that won the Royal Horticultural Society’s Award of Garden Merit in 2012, has a longer bloom season. It has double hose-in-hose flowers on very long (15 inch) spikes that stay on the plant for a very long time. The blossoms progressively turn pink as they deteriorate, then light tan.
- Little Honey measures 4′ high by 5′ broad. The golden yellow spring foliage, a sport of “Pee Wee,” gradually darkens to chartreuse green in June and then becomes red in the fall. For optimal results, give it morning sun and afternoon shade. Compared to other oakleaf hydrangea species, the white blooms’ 5 to 6-inch long, cone-shaped inflorescences are diminutive.
- ‘Munchkin’
4.5′ broad by 3′ high. The shrub breeding program at the U.S. National Arboretum in McMinnville, Tennessee, created Munchkin. It is the perfect option for modest home landscapes because of its compact form and dense plant habit. The flowers start out white and progressively change to a medium pink color.
- Pee Wee is usually 5 feet tall and 4 feet wide, but they can get bigger. Until quite late in the growing season, this upright, compact variety retains its deep burgundy and purple leaves before losing them. The leaves typically have 3 to 7 lobes and are on average 5 inches long. In the late summer, the flowers become tan.
- “Ruby Slippers” are 3.5″ high and 5″ broad. This mounding, semi-dwarf cultivar was created by the shrub breeding program of the U.S. National Arboretum through the crossbreeding of the cultivars “Snow Queen” and “Pee Wee.” The flowers begin as white but quickly change to a delicate pink hue, which later in the summer intensifies to rosy red.
- Sikes Dwarf is 2 to 4 feet tall and 3 to 4 feet wide. This compact collection works well in container gardens as well as smaller areas. The sterile florets in the flower clusters, which gradually turn light pink as they ripen, conceal the fertile blooms. ‘Sikes Dwarf’ has an asymmetrical spherical shape and an open plant habit.
The soil that Oakleaf hydrangea prefers has a pH of 5.06.5 and should be organic, fertile, well-drained, and slightly acidic. Once planted, it is drought hardy, though it does need water in extremely dry conditions. Effective drainage is crucial. Although the plant prefers moist soil, wet feet are intolerable.
Sunlight
In either complete or partial shade, this shrub can flourish. But it functions better when it receives at least a half-worth day’s of sunlight or more, which results in a better floral show, stronger stems, and more vibrant autumn foliage. Some varieties can tolerate a sunnier location. On the other hand, plants under heavy shadow will produce fewer blossoms but bigger leaves.
In general, Oakleaf Hydrangea trimming is little to nonexistent. Pruning should be done soon after the shrub flowers if it needs to be shaped or shrunk. In late summer, this shrub produces bloom buds for the following year. Or put another way, it grows on aged wood. Any other time of the year will result in the loss of the flowers for the following year when pruned.
Pests The only insects that occasionally harm this plant are spider mites and aphids. Deer will nonetheless munch on this plant, especially the sensitive, young spring foliage, so either use deer repellent or put up a physical barrier to protect it.
Propagation
Cuttings of the shrub’s stems can be used to multiply it. Layering is another method of plant propagation that can be used because the branches are low to the earth.
When used as a solitary specimen, a backdrop for smaller shrubs, bulbs, or perennials, a part of a mixed border, a deciduous hedge, or as part of a mass planting, oakleaf hydrangea is a multipurpose shrub that is bold yet graceful.
If there is a drawback to oakleaf hydrangeas, it is that a cautious gardener can find their enormous, rough-textured foliage intimidating. Rest certain that the foliage complements plants with smaller leaves extremely well. For instance, the contrast created by evergreens’ finer needles or scaly branches is appealing. Boxwoods’ smaller, more compact leaves and more formal round shape contrast nicely with the more relaxed shape of oakleaf hydrangeas. Oakleaf hydrangeas go nicely with taller ferns like ostrich or cinnamon ferns as well as shorter grass-like plants like liriope.
Easy-care Oakleaf hydrangea is particularly useful in the landscape since it provides year-round appeal. It has an immediate effect in the spring when its striking foliage first appears. Large, persistent clusters of creamy white or pink blooms stand out against the dark green leaves in the summer. Many cultivars develop to a medium pink or deep rose color over time. The oakleaf hydrangea especially shines in the fall with its deep, burgundy/purple foliage that lasts all the way through the winter. The pale brown or brownish dried flower heads provide more appeal. The tan bark’s exfoliation adds a new tactile dimension to the snowy scene in winter.
Should the fall be the time to prune oakleaf hydrangeas?
The oakleaf hydrangea is a deciduous, blooming shrub that works well for foundation planting, mass planting, and borders. Pink, light purple, and creamy white blooms blossom in the summer and fall. While only requiring a little trim once a year, this hydrangea doesn’t require extensive pruning. Oakleaf hydrangeas flower on growth from the previous season, so prune in the fall or the first few weeks of winter immediately following flowering.
What can I do to make my oak leaf hydrangea bloom?
“In a shady area, I have an oakleaf hydrangea that is seven years old. My hydrangea produces a lot of strong foliage, which I must frequently clip, but it does not flower. It only produced one or two blooms. What makes you believe that is? William Stovall queries.
When pruning this and other hydrangeas, timing is everything. The year before they blossom, oakleaf hydrangeas start to generate flower buds. Reduce pruning as much as possible to enhance the blooming show. Each year, just the broken and errant branches should be removed. This encourages the plant to blossom while assisting in controlling its size. Heavy pruning promotes growth, making the plant larger and necessitating further pruning. More stems with healthy flower buds are left over after selective pruning, resulting in a better bloom the following year.
Prune Like a Pro: Before making any cuts, consider the shape of the plant and use only clean, sharp equipment. By just removing a fourth to a third of the canopy each year, you can avoid overpruning.
On aged wood, does the oakleaf hydrangea bloom?
Native to the Southeast of the United States, oakleaf hydrangeas (Hydrangea quercifolia) are prized for their voluminous flower clusters and oak-like leaves. These plants are tolerant of USDA plant hardiness zones 5 through 9, but they develop slowly and may not blossom the first year. But with the right care, they bloom fairly predictably once they’re established. A paucity of blooms is typically the result of poor pruning techniques or insufficient watering. Both issues are easily fixable.
Before planting oakleaf hydrangea, work 2 to 4 inches of compost, moistened peat moss, or manure into the soil to a depth of 8 inches. These modifications enhance drainage and increase nutrients, which may encourage wholesome growth and blooms.
A soil test kit, available at nurseries and garden centers, can be used to determine the pH of the soil in your garden. The pH range between 5.5 and 6.5 is ideal for oakleaf hydrangea growth. To make the soil acidic, add sulfur, peat moss, sawdust, or dry leaves. Dig dolomitic lime into the soil to increase the pH.
Particularly in warmer areas, put oakleaf hydrangea in partial shade; the plant won’t thrive in dry, sunny settings and its blossoms may appear faded or burned. In complete shade, the plant could not flower.
To keep the soil equally moist but not soggy, water newly planted hydrangeas every other day or as necessary. In dry conditions, water established hydrangeas more frequently than once per week. Insert your finger into the ground. One inch beneath the surface should feel damp.
Early in the spring, fertilize oakleaf hydrangeas by applying 0.5 ounces of 10-10-10 fertilizer per 10 feet of soil. A surplus of fertilizer promotes lush, green growth rather than floral growth.
Oakleaf hydrangea should be pruned right away after blooming. If you prune an oakleaf hydrangea in the winter or spring, you’ll remove the flower buds and stop the plant from blooming for the season. Oakleaf hydrangeas bloom on old wood.
Which hydrangeas require pruning?
You can prune the first pair of buds on Hydrangea macrophylla, Hydrangea serrata, Hydrangea quercifolia, and Hydrangea aspera in the spring. In essence, you are removing the dried flower heads. By removing one or two of the oldest, largest stems, you can also help the plant become more open and give off a better shape. To promote fresh growth, cut these right back to the ground.
Hydrangea aborescens and Hydrangea paniculata can be clipped back more severely after flowering since flowers appear on fresh growth. These kinds don’t truly require pruning, although you can do it to prevent them from becoming too tall.